Metered quantity dispenser guns and mixer combination

ABSTRACT

An air operated material dispensing gun for emitting metered quantities wherein a piston is advanced and retracted in an actuation chamber of one housing with the piston having a displacement portion reciprocating in a displacement chamber cylinder of a second housing controlled by a one-way check valve allowing entry and a one-way check valve allowing exit of material to and from the displacement chamber respectively in conjunction with advancing and retracting strokes of the piston. The housings are divided by a nipple and seals through which the piston reciprocates with the nipple having a chamber, a radial relief and an atmospheric vent defining a neutral zone between the housings preventing air leaking to the material chamber and material from leaking to the air chamber. Two or more guns feed metered quantities of different materials to a driven mixer which blends the materials into a homogenized mixture and emits a metered amount of the mixture to use. The guns have an adjustable stop for limiting piston travel to adjust the metered quantity emitted by each gun and the cumulative quantity emitted by the mixer.

United States ate [72) lnventor Ronald E. Standlick 4506 Sudbury. Warren, Mich. 48093 [21] ApplrNo. 800.433 [2- Filed Feb.19,1969 [45] Patented Feb.2,l971

[54] METERED QUANTITY DISPENSER GUNS AND MIXER COMBINATION 8 Claims, 10 Drawing Figs.

[52] U.S.Cl 222/135, 222/334 [51] lnt.Cl B67d5/52 [50] FieldofSearch 222/135, 309, 334, 380, 383

[5 6] References Cited UNITED STATES PATENTS 484,383 10/1892 Weatherhead 222/334 1,504,423 8/1924 Boneberg. 222/334X 1,529,918 3/1925 Richards... 222/334X 1,965,038 7/1934 Hartman... 222/334X 3,221.948 12/1965 Kalist 222/334 3,254,806 6/1966 Madsen 222/334 Primary ExaminerSamuel F. Coleman Attorney-William T. Sevald ABSTRACT: An air operated material dispensing gun for emitting metered quantities wherein a piston is advanced and retracted in an actuation chamber of one housing with the piston having a displacement portion reciprocating in a displacement chamber cylinder of a second housing controlled by a one-way check valve allowing entry and a one-way check valve allowing exit of material to and from the displacement chamber respectively in conjunction with advancing and retracting strokes of the piston. The housings are divided by a nipple and seals through which the piston reciprocates with the nipple having a chamber, a radial relief and an atmospheric vent defining a neutral zone between the housings preventing air leaking to the material chamber and material from leaking to the air chamber. Two or more guns feed metered quantities of different materials to a driven mixer which blends the materials into a homogenized mixture and emits a metered amount of the mixture to use. The guns have an adjustable stop for limiting piston travel to adjust the metered quantity emitted by each gun and the cumulative quantity emitted by the mixer.

PATENTED'FEB 2l97l 3559848 SHEET 1 [1F 3 ATTORNFY PATENIED FEB 2 1971 SHEET 2 BF 3 m m m w w A .5 NW. 0 a M We W N .w\\ %\v\ N\N\\QGQRK 0 Y W01 uh, \L UE on B h v mm mm 93 R m m N v 0 h- R Ow MM 5% ATTORNEY M ETERED QUANTITY DISPENSER GUNS AND MIXER COMBINATION This invention relates to a novel gun for dispensing a metered quantity of material, the combination, of two or more such guns for dispensing ingredients metered relative to one another which are mixed later and/or the combination of two or more such guns with a mixer for mixing the ingredients and dispensing the mixture.

The dispensing gun singly or in plural combination and/or the guns and mixer combination are highly useful for supplying a metered small quantity of material and/or mixture for use where only a small quantity is needed from time to time and/or where fast setting mixtures of short pot life are metered such as epoxys, plastisols, polyesters, paints, oils, etc. and/or rapidly evaporating materials such as solvents, driers, etc.

An object of the invention is to provide a metering gun having displacement piston pump characteristics so that movement of the piston in one direction loads the gun with material h and movement of the piston in the other direction dispenses the material to use thereby eliminating pressurized containers or feeding pumps for supplying a metering device.

An object of the invention is to provide a positive loading metering and dispensing gun not dependent on pressurized containers or supply pumps and which is positively loaded by the displacement of the piston to insure accuracy in the quantity dispensed.

An object of the invention is to provide a gun operated by air or liquid pressure lending itself to easy automatic or semiautomatic operation and control.

An object of the invention is to provide an isolation zone in the dispensing gun between the air pressure in the actuation chamber and the material in the displacement chamber with the isolation zone communicating with atmosphere through vents to prevent leakage of air past the seals becoming mixed with the material in the displacement chamber and preventing leakage of the material past the seals from becoming mixed with the air in the actuation chamber to insure that the material is not contaminated by the introduction of air and to insure that the actuation chamber is free of material.

An object of the invention is to provide a piston displacement dispensing gun to insure accuracy in the dispensed quantity with the piston reciprocating between definite stops with at least one stop being adjustable to vary the piston stroke and resulting quantitative displacement to enable the user to accurately adjust the gun to a desired quantity. 7

An object of the invention is to provide a dispensing gun which has a normal position with the piston in the retracted or loaded position to condition the gun for immediate dispensing of the material.

An object of the invention is to provide a dispensing gun with dispensing controls mounted thereon operated by a hand lever or remote therefrom operated by a foot pedal to provide adaptability in the device.

An object of the invention is to provide means for combining several dispensing guns for operation by a threeway or four-way valve such as by a foot pedal or manually or by hand lever so that operation of the valve controls actuation of all the guns.

An object of the invention is to provide a combination of at least two guns together with a motorized mixing device with the guns supplying the mixing device with measured increments of material for mixing cognpounds or mixtures and emitting them in known desired metered quantities.

An object of the invention is to provide dispenser guns and a mixer and gun combination which is simple in design and construction, inexpensive to manufacture, easy to use, easy to maintain in top working condition and which is easily flushed and cleaned to insure maximum efficient working conditions.

These and other objects of the invention will become apparent by reference to the following description of the dispenser gun and its combination with like guns and/or with a mixing device embodying the invention taken in connection with the accompanying drawings in which:

FIG. 1 is a top plan view of the combination of the mixing device, dispensing guns, material containers, and a console and showing operation and control elements.

FIG. 2 is a face elevational view of the device seen in FIG. 2 with the containers broken away and the guns not shown to illustrate the face of the console.

FIG. 3. is a diagrammatic view of a foot pedal operated valve suitable for controlling gun operation.

FIG. 4 is an enlarged longitudinal cross-sectional view of a dispensing gun such as seen in FIG. 1, showing a gun embodying individual gun actuation controls.

FIG. 5 is a cross-sectional view of FIG. 4 taken on the line 5-5 thereof showing porting to the chambers of the gun.

FIG. 6 is a cross-sectional view of the device seen in FIG. 4 taken on the line 6-6 thereof showing the ports and chambers of the gun.

FIG. 7 is a partial cross-sectional view of a gun such as seen in FIG. 6 with parts broken away and with the valve housing and valve diagrammatically illustrated to show the ducts.

FIG. 8 is an enlarged cross-sectional view of the mixing device seen in FIGS. 1 and 2 showing the motor in elevation, illustrating the internal construction of the mixing device, and showing the rotor as taken on the line 8-8 of FIG. 10.

FIG. 9 is a bottom plan view of the base of the device of FIG. 8 illustrating the ports and channels in dotted lines; and

FIG. 10 is an enlarged plan view of a blade on the rotor of the mixer taken on the line 10-10 of FIG. 8.

Referring now to the drawings wherein like numerals refer to like and corresponding parts throughout the several views, the guns and mixer shown therein to illustrate the invention comprise a gun 20, FIG. 4, guns 21, FIG. 1, singly and in combination with each other and/or in combination with a mixing device 22, FIGS. 1 and 8.

More particularly, the gun 20, FIG. 4, includes a first housing 25 having an internal cylinder 26 relatively large in diameter defining an actuating chamber. A piston head 27 lies in the cylinder 26 dividing the actuating chamber into an advance portion 28 and a retract portion 29. A head seal 30 on the piston head 27 seals the chamber portions 28 and 29 relative to one another. A plug 31 threaded in the housing 25 closes the outer end of the cylinder 26. The plug 31 has a threaded bore 32. An adjusting screw 33 is threaded in the plug bore 32. The piston head 27 has a top surface 34 facing the screw 33. By axially adjusting the screw 33 relative to the piston 27 the travel of the piston head 27 toward the plug 31 may be adjustably limited to adjust the piston stroke as desired.

A nipple 35 is threaded in the housing 25. The nipple 35 has an internal bore forming an intermediate chamber 36, a radial relief 37 forming a neutral zone together with the chamber 36, and vents 38 leading from the radial relief 37 to atmosphere.

A second housing 40 has an internal cylinder 41 relatively small in diameter defining a displacement chamber. A displacement portion 42 of the piston lies in the cylinder 41 and is joined to the piston head 27 by a piston intermediate portion 43 which extends through the nipple 35. A first seal 44 in the nipple 35 seals against the piston intermediate portion 43 at the first housing 25 and a second seal 45 seals against the piston intermediate portion 43 at the second housing 40. The seals isolate the actuating and displacement chambers relative to the nipple 35 and also isolate the neutral zone chamber 36, relief 37, and vents 38 in the nipple 35.

A fitting 46 is threaded in the outer end of the second housing 40. The fitting 46 is equipped with a one-way ball check valve 47 allowing outlet of material from the displacement chamber cylinder 41 and prevents reverse flow. A nozzle 48 is screwed in the fitting 46. The second housing 40 has a radial inlet aperture 50. A material supply pipe 51 is threaded in the aperture and is equipped with a one-way ball check valve 52 allowing inlet of material to the displacement chamber cylinder 41 and preventing reverse flow.

A channel 55 in the first housing supplies air pressure to a three way valve 56, FIGS. 4 to 7. A port 57 vents the valve 56 to atmosphere. A port 58 leads from the valve 56 to the advance portion 28 of the actuating chamber at the piston head top surface 34. A port 59 leads from the valve 56 to the retract portion 29 of the actuating chamber. A shoulder 60 on the piston head 27 faces the retract portion 29. The piston head top surface 34 is much larger in area than the shoulder 60.

The valve 56 is so organized that air pressure is introduced via port 50 to the retract portion 29 faced by the shoulder 60 with the advance portion 28 vented to atmosphere via the port 57 so that normally the piston head 27 is moved against the stop screw 31 in its retracting stroke. A lever 61 on the housing 25 is in contact with a pin 62 which actuates the valve 56. By pressing the lever 61 the pin 62 moves the valve 56 to cut off vent 57 to atmosphere and to introduce air pressure in both the advance chamber 28 and the retract chamber 29 whereupon the larger area of the piston head top surface 34 moves the head 27 and piston in the advance stroke with the retract chamber 29 venting into the advance chamber 28 to advance the piston displacement portion 42 into the displacement chamber cylinder 41 whereupon material therein is forced past the valve 47 and out of the nozzle 48 as blocked by the valve 52. Upon completion of the advance stroke, the lever 61 is released and the piston head 27 retracts retracting the piston displacement portion 42 which draws material from the tube 51 past the valve 52 as blocked by the valve 47.

The guns 21 FIGS. 1 and 2, are the same as the gun except for channeling and porting as shown to illustrate four-way valve operation. Obviously the guns may be ported and operated by either a three-way or a four-way valve. A fourway valve 65, FIG. 3, is operated by a foot pedal 66 and has an air pressure supply port 67, a vent port 68 to atmosphere,"a pipe 69 to the retract chamber 29 at the piston shoulder 60 and a pipe 70 to the advance chamber 28 at the piston head top surface 34. The normal position of the four-way valve 65 is venting the advance chamber portion 28 to atmosphere and connecting the retract chamber portion 29 to air pressure to retract the piston head 27 against the stop screw to load the displacement chamber cylinder 41 with material. By depressing the pedal the condition of the valve is reversed and air pressure is fed to the advance chamber portion 28 and the retract chamber portion 29 is vented to atmosphere moving the piston in its advancing stroke to dispense a metered quantity of material. The pipes 69 and 70 lead from the valve 65, FIG. 3, to the guns 21, FIG. 1, as shown. The pipes 69 and 70 may lead through a lubricator 71 and filter 72, FIG. 6, which are mounted on a console 73.

Containers 74, 75 rest on the console 73 and support the guns 21 with their supply pipes 51 depending into the containers 74, 75. The mixing device 22 is mounted on the console 73. The mixing device 22 has base 77 and a case 78 mounted on the base 77 having an internal cavity 79, FIGS. 8- 10. The base 77 has channels 80 and 81 leading to the cavity 79. Tubes 82 and 83 lead from the fittings 46 on the guns 2] to the channels 80 and 81 respectively to feed material to the bottom of the cavity 79. The case 78 has a bottom bearing 84 and a top bearing 85. A rotor 86 in the cavity 79 is rotatably supported by the bearings 84, 85. A motor 87 drives the rotor 86 through a connector 88. The rotor has blades 89 having grooves 90 and orifices 91. The case 78 has a top channel 92 leading to a spout 93.

The guns 21 feed metered quantities of material to the bottom of the cavity 79 and upwardly through the cavity 79 to the channel 92 and spout 93. The' motor 87 and rotor 86 run as the material feeds past the blades 89 where it is sheared by the grooves 90 and orifices 91 to a homogenized mixture.

The console 73 may have a control valve 94, a running light 95, a solvent flush light 96, gauges 97 and 98 and throttle valves 99 and 100 as well as solvent and air purge valves 101 and 102 which are connected in the system to give the operator visual readings and adjustable control as will be understood in the art.

In operation with each gun 21 adjusted to delivery a desired metered quantity of material as by adjusting the stop 33 relative to the piston head 27, with the motor 87 and rotor 86 running, upon actuation of the valve 65 or valve 56. a metered quantity of homogenized mixture is dispensed from the spout 93 on the mixer 76.

The novel guns singly and in combination with each other and/or with a mixer provide an efficient means for dispensing accurately metered quantities of material as desired and while only preferred embodiments of the invention have been disclosed and described, the appended claims define the scope of the invention.

Iclaim: f

1. A gun for ejecting a metered quantity of material comprising:

a first housing having a diametrically relatively large cylinder defining an actuating chamber;

a second housing having a diametrically relatively small cylinder defining a displacement chamber;

each said housing having an end adjacent the other said housing and an opposite outer end;

a nipple interconnecting said housings at their adjacent ends with their said cylinders in axial alignment;

said nipple having an internal bore axially aligned with said cylinders;

a floating piston in said housings and nipple having a plunger portion at one end in said displacement chamber, an enlarged head on the other end in said actuating chamber and an intermediate portion in said bore;

a first seal in said nipple at said displacement chamber and a second seal in said nipple at said actuating chamber sealing against said intermediate portion of said piston;

a head seal on said piston head sealing against said cylinder of said first housing defining said actuating chamber;

said piston head having a shoulder surrounding said intermediate portion of said piston with said shoulder facing toward said nipple and saidsecond seal;

said piston head having a top surface facing said outer end of said first housing;

said piston head and said head seal dividing said actuating chamber into a retract portion facing said shoulder on said piston and an advance portion facing said top surface of said piston head; 9

said first housing having a first channel leading to said retract portion of said actuating chamber for introducing air pressure bearing against said piston head shoulder;

said first housing having a second channel leading to said advance portion of said actuating chamber for introducing air pressure bearing against piston head top;

said second housing having an inlet port for admitting material to said displacement chamber and an exit port for emitting material from said displacement chamber;

said second housing having means for connecting a first one-way check valve to said inlet port for passing material into said displacement chamber and preventing material flow therefrom and having means for connecting a second one-way check valve to said outlet port for passing material out of said displacement chamber and preventing material flow thereinto;

said first housing having means for connecting said channels to valve means for selectively introducing air pressure into said retract and advanced portions of said actuating chamber at said shoulder and head top surface respec tively to retract said plunger portion of said piston out of said displacement chamber to draw material into said displacement chamber and to advance said plunger portion of said piston into said displacement chamber to force material out of said displacement chamber;

movement of said piston retracting said piston plunger portion out of said displacement chamber with said inlet port connected to a supply of material by a duct and through said a first one-way check valve as blocked by said second one-way valve at said exit port creating low pressure in said displacement chamber whereby atmospheric pressure or greater on the material forces material into said displacement chamber; and

movement of said piston advancing said piston plunger portion into said displacement chamber with said exit port connected to an exit duct through said second one-way check valve as blocked by said first one-way check valve at said inlet port creating high pressure in said displacement chamber whereby atmospherical pressure on greater on the exit duct is overcome and the material in the displacement chamber is forced out of said exit port.

2. In a gun as set forth in claim 1:

said first housing having a valve chamber, a duct from said valve chamber to atmosphere, a duct from said valve chamber to said actuation chamber retract portion, a duct from said valve chamber to said actuation chamber advance portion, and a duct from said valve chamber to air pressure supply;

a valve core in said valve chamber having a normal position channeling air pressure supply to said actuation chamber retract portion via said ducts and channeling said actuation chamber advance portion to atmosphere via said ducts to normally retract said piston to load said displacement chamber cylinder with material;

a valve core actuator pin;

a lever mounted on said second housing for depressing said pin against said core;

said valve core, valve chamber, and ducts being so coordinated that depressing said lever and pin against said valve core moves said valve core from its normal position to a dispense position;

said dispense position of said valve core sealing off said duct to atmosphere and channeling air pressure to both the advance and retract portions of said actuation chamber; and

force developed by air pressure on said large area of said head top surface overcoming the force developed by air pressure on the small area of said shoulder of said piston to move the piston head in its advance stroke to dispense material from said displacement chamber with air pressure from said retract chamber portion back feeding to said advance chamber portion via said ducts, valve chamber and valve core,

3. In a device as set forth in claim 1, a four-Way, valve having an air pressure duct, an atmospheric duct, a tube leading to said gun retract chamber portion, and a tube leading to said advance chamber portion; said valve having a normal position supplying air pressure to said retract chamber portion and venting said advance chamber portion to atmosphere to normally retract said piston head and said piston displacement portion from said displacement chamber cylinder to load material in same; and

said valve having a dispense position supplying air pressure to said advance chamber portion and venting said retract chamber portion to atmosphere to advance said piston head and said piston displacement portion into said displacement chamber cylinder to eject material from same.

4. In a gun as set forth in claim 1, said nipple having a radial relief internally between said first and second seals creating a neutral zone between said housings; said nipple having at least one aperture leading from said neutral zone to atmosphere constituting a neutral zone vent. said neutral zone receiving leakage of material and air past said first and second seals respectively and said aperture venting leakage to atmosphere thereby preventing introduction of air into the material in said displacement chamber and preventing the introduction of material into said actuating chamber;

5 In a gun as set forth in claim 1, an axially adjustable stop on one said housing lying in one said cylinder for abutting said piston to selectively limit the travel of said piston to provide means for changing the volumetric displacement of said piston by controlling the stroke distance of said piston.

6. In a gun as set forth in claim 1, a like gun as set forth in claim 1 in combination therewith:

each said gun having an exit duct;

a common receiver communicating with both said exit ducts;

each said gun having an inlet duct feeding from a different container having different material, and

said guns thereby drawing metered quantities of different materials from different containers and delivering metered quantities of different materials to said common receiver.

7. In a combination as set forth in claim 6 said common receiver being a mixing device; said mixing device comprising:

a case having an internal cavity;

said case having opposite ends;

a base on one end of said case having at least two feed channels leading to said cavity of said case and having means for connecting tubes to said base leading to said channels;

a tube leading from said outlet port of each said gun to one said connecting means and one said channel in said base for introducing a metered quantity of material from each said gun to said cavity of said case;

a head on the other said end of said case; bearings in said head and said base aligned with said cavity of said case;

a rotor having blades rotatably positioned in said cavity of said case on said bearings;

a motor on one said base and head connected to said rotor to drive said rotor rotationally;

said case having a mixture emission port at an end of said case opposite to said feed channels;

a spout on said case connected to said mixture emission port;

said guns force feeding material to said mixing device,

through said case internal, cavity, and out said case emission port and said spout; and

said motor rotating said rotor to mix the materials in said cavity of said case as the materials are fed through said cavity by said guns.

8. In a mixing device as set forth in claim 7, said blades on said rotor each comprising a discular flange having a plurality of slots and grooves lying parallel to the flow of materials in said case; said blades in rotating swinging said slots and grooves at right angles to said material as its flows to shear the materials as they flow past said blades while said blades are rotating to mix the materials with each other in a thoroughly homogenized mixture. 

1. A gun for ejecting a metered quantity of material comprising: a first housing having a diametrically relatively large cylinder defining an actuating chamber; a second housing having a diametrically relatively small cylinder defining a displacement chamber; each said housing having an end adjacent the other said housing and an opposite outer end; a nipple interconnecting said housings at their adjacent ends with their said cylinders in axial alignment; said nipple having an internal bore axially aligned with said cylinders; a floating piston in said housings and nipple having a plunger portion at one end in said displacement chamber, an enlarged head on the other end in said actuating chamber and an intermediate portion in said bore; a first seal in said nipple at said displacement chamber and a second seal in said nipple at said actuating chamber sealing against said intermediate portion of said piston; a head seal on said piston head sealing against said cylinder of said first housing defining said actuating chamber; said piston head having a shoulder surrounding saiD intermediate portion of said piston with said shoulder facing toward said nipple and said second seal; said piston head having a top surface facing said outer end of said first housing; said piston head and said head seal dividing said actuating chamber into a retract portion facing said shoulder on said piston and an advance portion facing said top surface of said piston head; said first housing having a first channel leading to said retract portion of said actuating chamber for introducing air pressure bearing against said piston head shoulder; said first housing having a second channel leading to said advance portion of said actuating chamber for introducing air pressure bearing against piston head top; said second housing having an inlet port for admitting material to said displacement chamber and an exit port for emitting material from said displacement chamber; said second housing having means for connecting a first one-way check valve to said inlet port for passing material into said displacement chamber and preventing material flow therefrom and having means for connecting a second one-way check valve to said outlet port for passing material out of said displacement chamber and preventing material flow thereinto; said first housing having means for connecting said channels to valve means for selectively introducing air pressure into said retract and advanced portions of said actuating chamber at said shoulder and head top surface respectively to retract said plunger portion of said piston out of said displacement chamber to draw material into said displacement chamber and to advance said plunger portion of said piston into said displacement chamber to force material out of said displacement chamber; movement of said piston retracting said piston plunger portion out of said displacement chamber with said inlet port connected to a supply of material by a duct and through said a first oneway check valve as blocked by said second one-way valve at said exit port creating low pressure in said displacement chamber whereby atmospheric pressure or greater on the material forces material into said displacement chamber; and movement of said piston advancing said piston plunger portion into said displacement chamber with said exit port connected to an exit duct through said second one-way check valve as blocked by said first one-way check valve at said inlet port creating high pressure in said displacement chamber whereby atmospherical pressure on greater on the exit duct is overcome and the material in the displacement chamber is forced out of said exit port.
 2. In a gun as set forth in claim 1: said first housing having a valve chamber, a duct from said valve chamber to atmosphere, a duct from said valve chamber to said actuation chamber retract portion, a duct from said valve chamber to said actuation chamber advance portion, and a duct from said valve chamber to air pressure supply; a valve core in said valve chamber having a normal position channeling air pressure supply to said actuation chamber retract portion via said ducts and channeling said actuation chamber advance portion to atmosphere via said ducts to normally retract said piston to load said displacement chamber cylinder with material; a valve core actuator pin; a lever mounted on said second housing for depressing said pin against said core; said valve core, valve chamber, and ducts being so coordinated that depressing said lever and pin against said valve core moves said valve core from its normal position to a dispense position; said dispense position of said valve core sealing off said duct to atmosphere and channeling air pressure to both the advance and retract portions of said actuation chamber; and force developed by air pressure on said large area of said head top surface overcoming the force developed by air pressure on the small area of said shoulder of said piston to move the piston head in its advance stroke to dispense maTerial from said displacement chamber with air pressure from said retract chamber portion back feeding to said advance chamber portion via said ducts, valve chamber and valve core.
 3. In a device as set forth in claim 1, a four-way, valve having an air pressure duct, an atmospheric duct, a tube leading to said gun retract chamber portion, and a tube leading to said advance chamber portion; said valve having a normal position supplying air pressure to said retract chamber portion and venting said advance chamber portion to atmosphere to normally retract said piston head and said piston displacement portion from said displacement chamber cylinder to load material in same; and said valve having a dispense position supplying air pressure to said advance chamber portion and venting said retract chamber portion to atmosphere to advance said piston head and said piston displacement portion into said displacement chamber cylinder to eject material from same.
 4. In a gun as set forth in claim 1, said nipple having a radial relief internally between said first and second seals creating a neutral zone between said housings; said nipple having at least one aperture leading from said neutral zone to atmosphere constituting a neutral zone vent, said neutral zone receiving leakage of material and air past said first and second seals respectively and said aperture venting leakage to atmosphere thereby preventing introduction of air into the material in said displacement chamber and preventing the introduction of material into said actuating chamber.
 5. In a gun as set forth in claim 1, an axially adjustable stop on one said housing lying in one said cylinder for abutting said piston to selectively limit the travel of said piston to provide means for changing the volumetric displacement of said piston by controlling the stroke distance of said piston.
 6. In a gun as set forth in claim 1, a like gun as set forth in claim 1 in combination therewith: each said gun having an exit duct; a common receiver communicating with both said exit ducts; each said gun having an inlet duct feeding from a different container having different material, and said guns thereby drawing metered quantities of different materials from different containers and delivering metered quantities of different materials to said common receiver.
 7. In a combination as set forth in claim 6 said common receiver being a mixing device; said mixing device comprising: a case having an internal cavity; said case having opposite ends; a base on one end of said case having at least two feed channels leading to said cavity of said case and having means for connecting tubes to said base leading to said channels; a tube leading from said outlet port of each said gun to one said connecting means and one said channel in said base for introducing a metered quantity of material from each said gun to said cavity of said case; a head on the other said end of said case; bearings in said head and said base aligned with said cavity of said case; a rotor having blades rotatably positioned in said cavity of said case on said bearings; a motor on one said base and head connected to said rotor to drive said rotor rotationally; said case having a mixture emission port at an end of said case opposite to said feed channels; a spout on said case connected to said mixture emission port; said guns force feeding material to said mixing device, through said case internal, cavity, and out said case emission port and said spout; and said motor rotating said rotor to mix the materials in said cavity of said case as the materials are fed through said cavity by said guns.
 8. In a mixing device as set forth in claim 7, said blades on said rotor each comprising a discular flange having a plurality of slots and grooves lying parallel to the flow of materials in said case; said blades in rotating swinging said slots and grooves at right angles to said material as its flows to shear the materials as they flow past said blades while said blades are rotating to mix the materials with each other in a through homogenized mixture. 